2424#include <errno.h>
2525#include "virtualbox.h"
2626
27+ // From virtualbox/include/VBox/HostServices/GuestPropertySvc.h
28+ #define GUEST_PROP_FN_GET_PROP 1
29+ #define GUEST_PROP_FN_DEL_PROP 4
30+
2731static void _cleanup_close (int * fd ) {
2832 if (* fd != -1 ) {
2933 close (* fd );
@@ -86,13 +90,16 @@ static int connect(int fd, uint32_t *client_id) {
8690}
8791
8892static int get_prop (int fd , uint32_t client_id , const char * name , void * * value , size_t * size ) {
93+ // xref VbglR3GuestPropRead() in
94+ // virtualbox/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibGuestProp.cpp
95+
8996 // init header
9097 size_t msg_size = sizeof (struct vbg_ioctl_hgcm_call ) + 4 * sizeof (struct vmmdev_hgcm_function_parameter64 );
9198 struct vbg_ioctl_hgcm_call _cleanup_free_ * msg = calloc (1 , msg_size );
9299 // init_header re-adds the size of msg->hdr
93100 init_header (& msg -> hdr , msg_size - sizeof (msg -> hdr ), msg_size - sizeof (msg -> hdr ));
94101 msg -> client_id = client_id ;
95- msg -> function = 1 ; // GUEST_PROP_FN_GET_PROP
102+ msg -> function = GUEST_PROP_FN_GET_PROP ;
96103 msg -> timeout_ms = -1 ; // inf
97104 msg -> interruptible = 1 ;
98105 msg -> parm_count = 4 ;
@@ -147,6 +154,38 @@ static int get_prop(int fd, uint32_t client_id, const char *name, void **value,
147154 }
148155}
149156
157+ static int del_prop (int fd , uint32_t client_id , const char * name ) {
158+ // xref VbglR3GuestPropDelete() in
159+ // virtualbox/src/VBox/Additions/common/VBoxGuest/lib/VBoxGuestR3LibGuestProp.cpp
160+
161+ // init header
162+ size_t msg_size = sizeof (struct vbg_ioctl_hgcm_call ) + sizeof (struct vmmdev_hgcm_function_parameter64 );
163+ struct vbg_ioctl_hgcm_call _cleanup_free_ * msg = calloc (1 , msg_size );
164+ // init_header re-adds the size of msg->hdr
165+ init_header (& msg -> hdr , msg_size - sizeof (msg -> hdr ), msg_size - sizeof (msg -> hdr ));
166+ msg -> client_id = client_id ;
167+ msg -> function = GUEST_PROP_FN_DEL_PROP ;
168+ msg -> timeout_ms = -1 ; // inf
169+ msg -> interruptible = 1 ;
170+ msg -> parm_count = 1 ;
171+
172+ // init arguments
173+ struct vmmdev_hgcm_function_parameter64 * params = (void * ) (msg + 1 );
174+ // property name (in)
175+ params [0 ].type = VMMDEV_HGCM_PARM_TYPE_LINADDR_IN ;
176+ params [0 ].u .pointer .size = strlen (name ) + 1 ;
177+ params [0 ].u .pointer .u .linear_addr = (uintptr_t ) name ;
178+
179+ // delete value
180+ if (ioctl (fd , VBG_IOCTL_HGCM_CALL_64 (msg_size ), msg )) {
181+ return VERR_GENERAL_FAILURE ;
182+ }
183+ if (msg -> hdr .rc != VINF_SUCCESS ) {
184+ return msg -> hdr .rc ;
185+ }
186+ return VINF_SUCCESS ;
187+ }
188+
150189static int disconnect (int fd , uint32_t client_id ) {
151190 struct vbg_ioctl_hgcm_disconnect msg = {
152191 .u = {
@@ -162,7 +201,7 @@ static int disconnect(int fd, uint32_t client_id) {
162201 return msg .hdr .rc ;
163202}
164203
165- int virtualbox_get_guest_property ( char * name , void * * value , size_t * size ) {
204+ static int start_connection ( uint32_t * client_id ) {
166205 // clear any previous garbage in errno for error returns
167206 errno = 0 ;
168207
@@ -179,12 +218,26 @@ int virtualbox_get_guest_property(char *name, void **value, size_t *size) {
179218 }
180219
181220 // connect to property service
182- uint32_t client_id ;
183- ret = connect (fd , & client_id );
221+ ret = connect (fd , client_id );
184222 if (ret != VINF_SUCCESS ) {
185223 return ret ;
186224 }
187225
226+ // return fd
227+ ret = fd ;
228+ fd = -1 ;
229+ return ret ;
230+ }
231+
232+ int virtualbox_get_guest_property (char * name , void * * value , size_t * size ) {
233+ // connect
234+ uint32_t client_id ;
235+ int ret = start_connection (& client_id );
236+ if (ret < 0 ) {
237+ return ret ;
238+ }
239+ int _cleanup_close_ fd = ret ;
240+
188241 // get property
189242 ret = get_prop (fd , client_id , name , value , size );
190243 if (ret != VINF_SUCCESS ) {
@@ -206,3 +259,32 @@ int virtualbox_get_guest_property(char *name, void **value, size_t *size) {
206259 errno = 0 ;
207260 return 0 ;
208261}
262+
263+ int virtualbox_delete_guest_property (char * name ) {
264+ // connect
265+ uint32_t client_id ;
266+ int ret = start_connection (& client_id );
267+ if (ret < 0 ) {
268+ return ret ;
269+ }
270+ int _cleanup_close_ fd = ret ;
271+
272+ // delete property
273+ ret = del_prop (fd , client_id , name );
274+ if (ret != VINF_SUCCESS ) {
275+ disconnect (fd , client_id );
276+ return ret ;
277+ }
278+
279+ // disconnect
280+ ret = disconnect (fd , client_id );
281+ if (ret != VINF_SUCCESS ) {
282+ // we could ignore the failure, but better to make sure bugs
283+ // are noticed
284+ return ret ;
285+ }
286+
287+ // for clarity, ensure the Go error return is nil
288+ errno = 0 ;
289+ return 0 ;
290+ }
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